Fuel filter assembly

ABSTRACT

A fuel filter includes a manifold, a connector element, a filter bowl, a filter element, an inlet shutoff valve, an outlet shutoff valve, an inlet port, an inlet passage, an outlet port, an outlet passage and a relief valve in which the connector element is fixed to the manifold, and the filter bowl is reversibly fixed to the connector element, the connector element and the manifold define a chamber and the chamber is split into a second inlet chamber and a second outlet chamber by the relief valve. The filter bowl is adapted to reversibly receive the filter element and is so configured that when the filter element is located within the filter bowl and the filter bowl attached to the connection element, the filter element divides the space defined by the connector element and filter bowl into an inlet filter chamber and an outlet filter chamber.

FOREIGN PRIORITY

This application claims priority to Polish Patent Application No.P.433389 filed Mar. 30, 2020, the entire contents of which isincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to fuel filters and in particular to fuelfilters having a filter bypass valve and shutoff valves on the fuelinlet and outlets.

BACKGROUND

Known fuel filters comprise a filter bowl suitable for housing a filterelement, a filter element, and a manifold to which the filter bowl maybe reversibly attached. The manifold includes fuel inlet and outletports. In combination the manifold, filter bowl and the filter elementdefine a flow path in which fuel flows into the manifold through thefuel inlet port, through the filter element and out of the manifold viathe fuel outlet port.

SUMMARY

According to an aspect of this disclosure there is provided a fuelfilter comprising a manifold, a connector element, a filter bowl, afilter element, an inlet shutoff valve, an outlet shutoff valve, aninlet port, an inlet passage, an outlet port, an outlet passage and arelief valve in which: the connector element is fixed to the manifold,and the filter bowl is reversibly fixed to the connector element, theconnector element and the manifold define a chamber and the chamber issplit into a second inlet chamber and a second outlet chamber by therelief valve, the filter bowl is adapted to reversibly receive thefilter element and is so configured that when the filter element islocated within the filter bowl and the filter bowl attached to theconnection element, the filter element divides the space defined by theconnector element and filter bowl into an inlet filter chamber and anoutlet filter chamber, the inlet port is incorporated in the manifold,and the inlet port and inlet filter chamber are in fluid communicationvia the inlet passage and the second inlet chamber, the outlet port isincorporated in the manifold and the outlet port and outlet filterchamber are in fluid communication via the outlet passage and the secondoutlet chamber, the inlet shutoff valve is biased by a biasing meansinto a closed configuration which prevents fuel flowing along the inletpassage when the filter bowl is not connected to the connector element,connection of the filter bowl to the connector element causes the inletshutoff valve to be impelled into an open configuration which allowsfuel to flow along the inlet passage, the outlet shutoff valve is biasedby a biasing means into a closed configuration which prevents fuelflowing along the outlet passage, the outlet shutoff valve is configuredto move into a closed configuration which prevents fuel flowing alongthe outlet passage when the filter bowl with a filter element within itis not connected to the connector element or there is no filter elementwithin the filter bowl, and connection of the filter bowl with a filterelement within it to the connector element causes the outlet shutoffvalve to be impelled into an open configuration which allows fuel toflow along the outlet passage, the relief valve is biased by a biasingmeans into a closed configuration so that fuel flowing between the inletpassage and outlet passage has to pass through the filter element, andmovement of the relief valve into an open configuration allows fuel toflow between the inlet passage and the outlet passage via the reliefvalve without the fuel passing through the filter element.

For the purposes of the present disclosure, reference to “fullyconnected” when referencing the connection of the filter bowl to theconnector element is to be understood to mean for connections such asscrew threaded connections that the filter bowl is screwed to theconnector element to the maximum extent possible.

References to upstream and downstream are with reference to the flow offuel through the fuel filter from the fuel filter inlet port through theinlet passage, into the filter inlet chamber, through the filter elementinto the filter outlet chamber, and through the outlet passage to theoutlet port.

In some embodiments of the above embodiment the impelling of the inletshutoff valve and the outlet shutoff valve into their open configurationcommences after commencement of connection of the fuel filter bowl withthe filter element within to the connector element and before the fuelfilter bowl is fully connected to the connector element.

An advantage of the fuel filter of the disclosure is that when thefilter bowl with the filter within it is not attached to the connectorelement the inlet and outlet shutoff valves are both in their closedconfigurations with the result that fuel does not leak out of theconnector element, manifold or fuel lines leading to and from the fuelinlet and fuel outlet ports respectively. This means that when servicingthe fuel filter, for example changing the filter element, the fuel linesdo not need to be detached from the manifold. It is further the casethat when the filter bowl is being detached from the connector means thebiasing means will cause the inlet and outlet shutoff valves toautomatically move into their closed configurations. As such, theremoval of the filter bowl is expected to leave the person removing thefilter bowl with some fuel in the filter bowl which can then be safelystored or disposed of but there will be no fuel leaking from themanifold or connector element. These advantages have the result thatservicing the fuel filter can be simple and swift and as such the costsassociated with such a servicing can be minimised.

A further advantage of the fuel filter of the disclosure is that theoutlet shutoff valve will not move to the open configuration unlessthere is a filter element within the filter bowl. This may prevent theaccidental attachment of the filter bowl without a filter element andsubsequent use of the fuel filter without a filter element despite auser believing a filter element to be present.

A further advantage of the fuel filter of the disclosure is that theconnector element can be adapted to be attached to existing knownconfigurations of fuel filter manifolds. This has the result that a fuelfilter of the current disclosure can be fitted to an existing mechanismwhich incorporates a fuel filter, for example a gas turbine engine forus in an aircraft, without having to change the manifold.

A further advantage of the disclosure is that mechanically the fuelfilter of the disclosure is relatively simple and can be made to acompact design. This can lead to a high degree of reliability and againreduced maintenance costs.

The filter bowl is configured to have the form of a bowl with an openmouth within which a filter element may be reversibly mounted. In someembodiments of the above embodiments of the current disclosure thefilter bowl is connected to the connector element via a screw threadadjacent to the open mouth of the filter bowl and a corresponding threadon the connector element. In some other embodiments the filter bowl isconnected to the connector element via other mechanical engagement meanswhere the act of connection of the filter bowl to the connector elementmeans causes the filter bowl generally, and the base of the filter bowland filter element specifically, to move closer to the connector elementas connection occurs.

In some embodiments of the above embodiments the relief valve is causedto move into its open configuration when a predetermined fuel pressureis reached within the inlet passage and inlet chamber. This isadvantageous because in normal operating conditions a fuel pump willpump fuel into the fuel filter and the fuel pressure within the inletpassage and inlet chamber will, among other factors, be a function ofthe pumping, the pressure drop across the filter element, and therelated flow rate of fuel through the filter element. As the filterelement traps material in the material of the filter the pressure dropacross the filter element increases and the flow rate decreases untilthe filter element is sufficiently blocked that there is insufficientflow through the filter element. When the fuel within the inlet passageand inlet chamber reaches a predetermined pressure the pressure reliefvalve will be pushed open by the pressurised fuel. Fuel will then flowdirectly from the inlet passage or inlet chamber to the outlet chamberor outlet passage. This ensures that sufficient fuel exits the fuelfilter via the fuel outlet port for continued operation of the mechanismin which the fuel filter of this disclosure is incorporated. Fuel willcontinue to flow through the relief valve until the fuel pressure withinthe inlet passage and inlet chamber drops below the predeterminedpressure at which time the relief valve will revert to its closedconfiguration.

The maximum rate of flow of fuel through the fuel filter can bepredetermined by designing the filter element and filter bowl to allow amaximum predetermined rate of fuel flow to occur. A non-limiting exampleof such a maximum desired fuel flow is 20 000 pph (2.520 Kg/s).

In some embodiments of the above embodiments of the current disclosurethe second inlet chamber is defined by the manifold, the connectorelement and a portion of the relief valve, and the portion of the secondinlet chamber that is defined by the portion of the connector elementhas one or more side walls and a second end wall. The portion of thesecond inlet chamber that is defined by the portion of the connectorelement has a cross section in a plane parallel to the second end wallthat is the same at all positions in that portion. The manifold andconnector element defining the second inlet chamber also define a firstand second inlet chamber apertures respectively. The first inlet chamberaperture is a mouth of the portion of the inlet passage extending fromthe fuel inlet port, the second inlet chamber aperture passes throughthe second end wall and at least one sliding seal means extends aroundthe edge or inner face of the second inlet chamber aperture, the inletshutoff valve comprises a longitudinally extending conduit element, theconduit element is configured to extend through the second inlet chamberaperture in a fuel tight sliding engagement with the sliding seal means,the conduit element comprises a first flanged end, a second end, and oneor more side walls, the first end of the conduit element is closed, theflange of the first end of the conduit element comprises a flangeelement which extends laterally (relative to the longitudinal axis ofthe conduit element) from the first end of the conduit element and hasan outer edge spaced from the conduit element, the flange elementdefines at least one aperture passing through the flange, the flangeelement is dimensioned and configured so that its outer edge is insliding contact with the or each side wall of the second inlet chamber,the one or more side walls of the conduit element extend between thefirst and second ends and at least one side wall of the conduit elementdefines at least one first fuel aperture passing through the side wallat a position adjacent to or close to the first end, the conduit elementis biased by a first biasing means to move to a position where theflange element of the conduit element is impelled against the second endwall of the second inlet chamber, and a seal means adapted to seal eachof the flange apertures when the flange element of the conduit elementis impelled against the second end wall of the second inlet chamber isattached to one or both of the face of the flange plate facing thesecond end wall of the second inlet chamber and the face of the secondend wall of the second inlet chamber facing the flange plate.

In some embodiments of this embodiment the portion of the second inletchamber is defined by the manifold, the connector element and a portionof the relief valve, and the portion of the second inlet chamber that isdefined by the portion of the connector element has one or more sidewalls and a second end wall, the portion of the second inlet chamberthat is defined by the portion of the connector element has a crosssection in a plane parallel to the second end wall that is the same atall positions in that portion, the manifold and connector elementdefining the second inlet chamber also define a first and a second inletchamber aperture respectively, the first inlet chamber aperture is amouth of the portion of the inlet passage extending from the fuel inletport, the second inlet chamber aperture passes through the second endwall and at least one sliding seal means extends around the edge orinner face of the second inlet chamber aperture, the inlet shutoff valvecomprises a longitudinally extending conduit element, the conduitelement is configured to extend through the second inlet chamberaperture in a fuel tight sliding engagement with the sliding seal means,the conduit element comprises a first end, a second end, and one or moreside walls, the first end of the conduit element is closed and providedwith a flange which extends laterally (relative to the longitudinal axisof the conduit element) from the first end of the conduit element, theone or more side walls of the conduit element extend between the firstand second ends, at least one side wall of the conduit element definesat least one first fuel aperture passing through the side wall at aposition adjacent to or close to the first end, the conduit element isbiased by a first biasing means to move to a position where the flangeof the conduit element is impelled against the second end wall of thesecond inlet chamber, and a seal means is provided which is adapted toseal the second inlet chamber aperture when the flange element of theconduit element is impelled against the second end wall of the secondinlet chamber.

In this embodiment the conduit element acts as part of the inlet passageand the inlet shutoff valve. The inlet shutoff valve has an openconfiguration in which the flange element is spaced from the second endwall of the second inlet chamber and fuel can flow through around theflange and into the conduit element via the first fuel apertures, and aclosed configuration in which the flange element of the conduit elementis impelled against the second end wall of the second inlet chamber andfuel cannot flow into the first fuel apertures.

The second end of the conduit element or a portion of the conduitelement extending from the first end of the conduit element forms partof the inlet passage and may, in some embodiments, be located in theinlet filter chamber. The second end of the conduit element can be open,or the conduit element may be of other configurations that allow fuelthat enters the conduit element via the first fuel apertures to exit theconduit element.

The advantage of this embodiment is that any fuel in the conduit elementwhen the filter bowl is removed from the connector element may beexpected to drain into the filter bowl.

In some embodiments of the above embodiments of the current disclosurethe conduit element further comprises one or more second fuel apertureswhich are defined by one or more of the side walls of the conduitelement, the one or more second fuel apertures are locatedlongitudinally between the one or more first fuel apertures and thesecond end of the conduit element, and the conduit element isdimensioned and configured so that when the filter bowl is fullyattached to the connector element the second end of the conduit elementabuts a part of the filter bowl, the apertures in the flange of theconduit element are not sealed, the first fuel apertures of the conduitelement open into the second inlet chamber, and the second fuelapertures of the conduit element open into the inlet filter chamber.

In these embodiments the second fuel apertures are longitudinally spacedfrom the first fuel apertures and separated by a blank portion of theconduit element. This blank portion includes no apertures through theside wall or walls of the conduit element.

In some embodiments where the filter bowl is screwed onto the connectorelement, the second end of the conduit element connects with the portionof the filter bowl at or adjacent to the intersection of the filter bowland the axis of the thread on the filter bowl that engages with theconnector element.

An advantage of these embodiments is that the conduit element can be sodimensioned that the filter bowl does not make contact with the conduitelement until the filter bowl is at least partially attached to theconnector element. This avoids the inlet shutoff valve being opened tooearly leading to accidental spillage of fuel as the filter bowl isattached to the connector element.

In some embodiments of the above embodiment of the current disclosurethe fuel filter further comprises an intermediate structure, in whichthe second end of the conduit element abuts a part of the filter bowlvia the intermediate structure when the filter bowl is fully attached tothe connector element, and the intermediate structure is configured anddimensioned so that the biasing means may displace the intermediatestructures and move the conduit element into the closed configurationwhen the filter bowl is detached from the connection element.

In some other embodiments of the above embodiment of the currentdisclosure the fuel filter further comprises an intermediate structure,in which the second end of the conduit element abuts a part of thefilter bowl via the intermediate structure when the filter bowl is fullyattached to the connector element, and the intermediate structure isintegral to or attached to the filter bowl.

In either of the above embodiments with an intermediate structure, theintermediate structure may also be so dimensioned, located andconfigured that it serves to locate and or retain the filter element inthe filter bowl. The intermediate structure may be in sliding fit with aportion of the filter element so as to retain the filter element in thefilter bowl.

In some embodiments of the above embodiments of the current disclosurethe portion of the manifold that partially defines the second outletchamber defines a first outlet chamber aperture, and the portion of theconnector element partially defining the second outlet chamber alsodefines one or more second outlet chamber apertures, the first outletchamber aperture is a mouth of the portion of the outlet passageextending from the fuel outlet port, the or each second outlet chamberaperture is in fluid communication with the outlet filter chamber, theoutlet shutoff valve comprises an aperture closure element, the apertureclosure element is configured to overlie all of the second outletchamber apertures and to be movable between a closed configuration inwhich the aperture closure element seals all of the second outletchamber apertures and an open configuration spaced from the secondoutlet chamber apertures, and the aperture closure element is biasedinto the closed configuration by the biasing means.

One or both of the face of the aperture closing means facing themanifold and or connection element defining the second outlet chamberapertures, and the face of the manifold and or connection elementdefining the second outlet chamber apertures facing the aperture closingmeans is provided with a means for sealing the second outlet chamberapertures when the aperture closing means is impelled against themanifold and or connection element defining the second outlet chamberapertures.

A number of second outlet chamber apertures may be included in the fuelfilter of the present disclosure so that there is no restriction on theflow of fuel out of the outlet filter chamber through the second chamberapertures.

In some embodiments of the above embodiments of the current disclosurethe fuel filter comprises one or more outlet intermediate structures,each outlet intermediate structures are dimensioned and configured tocontact a portion of the filter element at least when the filter bowl isfully attached to the connector element and the filter element is withinthe filter bowl, each outlet intermediate structure impels the apertureclosure means into its open configuration when the filter bowl is fullyattached to the connector element, and the filter element is correctlylocated within the filter bowl, and the one or more outlet intermediatestructures allow the biasing means to displace each of the outletintermediate structures and move the aperture closure means into theclosed configuration when the filter bowl and filter element aredetached from the connection element.

An advantage of this embodiment of the present disclosure is that eachsecond outlet chamber aperture is automatically closed as the filterbowl/filter element is moved away from the connector element.

An advantage of this embodiment is that the or each outlet intermediatestructure can be so dimensioned that the filter element does not makecontact with those structures or the structures do not make contact withthe aperture closure means until the filter bowl is at least partiallyattached to the connector element. This again avoids any accidentalspillage of fuel as the filter bowl is attached to the connectorelement.

In some embodiments of the above embodiments of the current disclosureat least one or both of the biasing means of the inlet and outletshutoff valves is a compression spring.

In some embodiments of the above embodiments of the current disclosurethe relief valve comprises a means for adjusting the force with whichthe biasing means biases the relief valve into its closed configuration.This has the advantage that the relief valve may be calibrated to openat a specific predetermined fuel pressure in the filter inlet chamberand inlet filter passage. In some embodiments, the adjustment may beperformed by the insertion or removal of shims between one end of thebiasing means and whatever structure that end of the biasing means isbearing against.

In some embodiments of the above embodiments of the current disclosurethe relief valve comprises a valve seat and a valve plug, the biasingmeans biases the valve plug against the valve seat (the closedconfiguration of the relief valve), and the valve plug may be impelledto move to a position spaced from the valve seat (the open configurationof the relief valve).

In some embodiments of the above embodiments of the current disclosurethe valve plug has valve face with a frustoconical configuration and thevalve seat is configured accordingly.

In some embodiments of the above embodiments of the current disclosurethe valve plug comprises a valve face, a pressure face, and one or morewalls that define a valve plug passage, in which the valve face isadapted to form a seal with the valve seat, the valve face extendsaround the outside of the wall or walls that define the valve plugpassage, the face of the wall or walls that face into the valve plugpassage partially define the second inlet chamber, the face of the wallor walls that face away from the valve plug passage partially define thesecond outlet chamber and a first end of the wall or walls is joined tothe valve face by the pressure face. In some embodiments, when the valveface has a frustoconical configuration, the valve plug pressure facejoins to the smaller diameter edge of the frustoconical valve face.

In such embodiments the valve seat and valve plug in part separate thesecond inlet chamber from the second outlet chamber.

In such embodiments the pressure face is included in the relief valve sothat the valve plug has a face that fuel pressure from the fuel in theinlet passage, second inlet chamber and the filter inlet chamber can acton so as to push the fuel plug away from the fuel seat so as to open therelief valve. The fuel can then flow directly from the second inletchamber into the second outlet chamber.

In some embodiments of the above embodiments of the current disclosurethe biasing means extends between and bears upon the valve plug of therelief valve and a portion of the manifold or connector element.

In some embodiments of the above embodiments the relief valve of thefuel filter of the present disclosure is formed from stainless steel4403, the or each biasing means from spring steel, the or each sealelement from a suitable fluorocarbon, and the remaining parts fromaluminium 6061 or aluminium T651. In other embodiments, other suitablematerials may be used to form the parts of the fuel filter.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described and explained by way ofexample with reference to the accompanying drawings in which:

FIG. 1 shows a perspective view of an embodiment of a fuel filter of thepresent disclosure;

FIG. 2 shows a first side view of the fuel filter of FIG. 1;

FIG. 3 shows a second side view of the fuel filter of FIG. 1;

FIG. 4 shows a section A-A of the fuel filter of FIG. 2;

FIG. 5 shows a section B-B of the fuel filter of FIG. 3;

FIG. 6 shows an exploded view of the components of the fuel filter ofFIG. 1;

FIG. 7 shows an enlarged view of the conduit element of the fuel filterof FIG. 1; and

FIGS. 8a and 8b show a schematic view of the outlet shutoff valve inopen and closed configurations.

DETAILED DESCRIPTION

With reference to FIGS. 1, 2 and 3, a fuel filter 2 is comprised of amanifold 4, to which is attach a connector element 6. Reversiblyconnected to the connector element 6 is a filter bowl 8.

The manifold 4 defines a fuel inlet port 10 and a fuel outlet port 12.The fuel inlet and outlet ports 10, 12 are provided with means (notshown) to engage with the ends of a fuel input line (not shown) and afuel output line (not shown) respectively.

With reference to FIGS. 4 and 5, to enhance the clarity of theseFigures, some elements described below and shown in these Figures arelabelled in only one of the Figures.

With reference to FIGS. 4, 5, 6, 7, 8 a and 8 b, the connector element 6is attached to the manifold 4 by a number of bolts 14 with an annulargasket 16 between the abutting faces of the connector element 6 andmanifold 4.

The filter bowl 8 is adapted to reversibly engage with the connectorelement 6 via a helical screw thread (not shown) which is formed on theface of a portion of the radially outer face of the filter bowl element70 and the radially inner face of connector element portion 72. Thescrew thread is dimensioned so that filter bowl element 70 may bescrewed into the connector element portion 72 until the stop 76 on thefilter bowl 8 abuts the edge 80 of the connector element portion 72.When the stop 76 on the filter bowl abuts the edge 80 of the connectorelement portion 72 the portion of the filter bowl element 70 furthestfrom the filter bowl base 78 is adjacent to the annular seals 74 and afuel tight seal is formed between the connector element portion 72 andthe filter bowl element 70. The annular seals 74, are retained in a pairof annular grooves (not labelled) in the inner face of connector elementportion 72.

The annular seals 74 are o rings and are formed of a fluorocarbon thatis suitable for high temperatures and which has good chemicalresistance, for example Viton® GLT which is available from DuPontPerformance Elastomers. This is also the material used in connectionwith other annular seals, in particular o rings, used in this embodimentof a fuel filter according to the current embodiment of the presentdisclosure.

The filter bowl 8 is configured and dimensioned to substantiallysurround a known filter element 110. The filter element 110 iscylindrical and constructed to filter fuel that is flowing radiallyoutwardly from an inlet filter chamber 92 in the inside of the cylinderof the filter element 110 to an outlet filter chamber 64 outside thefilter element 110.

The base 78 of the filter bowl 8 is configured to engage with a firstend of the filter element 110. The engagement is a push fit of thefilter element 110 onto a spindle 114. The push fit is sufficientlytight that fuel will not flow through the joint between the filterelement and the spindle 114.

The manifold 4 and connector element 6 define a chamber between thefaces 52, 54 and 22 of the manifold 4 and face 130 and walls 56, 24, and36 of the connector element 6. That chamber is split into second inletchamber 20 and second outlet chamber 50. Second inlet chamber 20 isdefined in part by a recess face 22 in the manifold 4, in part by avalve seat element 24 and wall 36 of the connector element 6, and inpart by valve plug 132.

Valve plug 132 is comprised of a valve face 134, a pressure face 136,and a cylindrical valve plug passage wall 138. The valve face 134 isconfigured to sealingly abut the valve seat face 142 of the valve seatelement 24 and is biased into that abutment by a biasing means 118 whichis compressed between the manifold 4 and the valve plug 132. The biasingmeans 118 is calibrated to exert a spring force that will be overcomeonce fuel in the second inlet chamber 20 achieves a predetermined fuelpressure.

The face of the valve plug passage wall 138 facing inwards, towards theopposite side of the valve plug passage wall 138, defines a part of thesecond inlet chamber 20. The valve plug passage wall 138 is in a slidingfit with the recess face 22 of manifold 4 and a sliding sealing means140, such as an o ring, creates a fuel tight seal between recess face 22and valve plug passage wall 138.

The manifold 4 defines an inlet passage 18 which extends from the fuelinlet port 10 to the second inlet chamber 20. The second inlet chamberrecess face 22, chamber element 24, wall 36 define substantiallycylindrical volumes and chamber element 24 is configured to be a slidingfit within the recess face 22. An annular seal 28, such as an o ring, isretained in an annular grove 26 in the radially outer surface of thechamber element 24 to form a fuel tight seal between the chamber element24 and recess face 22. The radially inner face of the chamber element 24thus constitutes the side wall and the second end wall of the secondinlet chamber is wall 36.

The second inlet chamber 20 has a first inlet chamber aperture 30 and asecond inlet aperture 32. The first inlet chamber aperture 30 is themouth of the inlet passage 18 into the second inlet chamber 20 andpasses through recess face 22 of the manifold 4. The second inletaperture 32 is defined by the wall 36 of the connector element 6 and theface of wall 36 defining the aperture 32 includes an annular grove (notlabelled) in which is retained an annular seal 34, such as an o ring.

The second inlet aperture 32 is circular in cross section (in the planeof the wall 36 of the connector element 4) and is dimensioned so that acylindrical conduit element 38 with a side wall 40 can pass through theaperture 32 and the side wall 40 of the conduit element is in a slidingfit with the face of the wall 36 defining the aperture 32. The annularseal 34 forms a fuel tight seal between the face of wall 36 defining theaperture 32 and the side wall 40 of the conduit element when the sidewall 40 has a blank portion that is a portion of the side wall 40without apertures.

The conduit element 38 has a first closed end 42 and, extendinglaterally from the closed end 42 is a radially extending flange plate44. The flange plate 44 defines a number of apertures 120, and has anouter edge 122.

The flange plate 44 is so dimensioned configured that the outer edge 122of the flange plate 44 is clear of the radially inner face of valve seatelement 24 of the connector element 6. The flange plate 44 is biasedtoward the wall 36 of the connector element 6 by a biasing means 124.This biases the conduit element 38 as a whole towards the base 78 of thefilter bowl 8. The face of the flange plate 44 facing the wall 36 has acoating of a flexible sealant (not shown). When the flange plate 44 isimpelled against the wall 36 the sealant forms a fuel tight seal betweenthe flange plate 44 and the wall 36 and fuel ceases to be able to flowthrough the apertures 120. This is the inlet shutoff valve in its closedconfiguration.

The biasing means 124 is compressed between the wall 36 of the connectorelement 6 and a circumferential ridge 144 that is retained in thecircumferential grove 146 in the side wall 40 of the conduit element 38.

Adjacent to and spaced from the closed end 42 on the side wall 40 of theconduit element 38 are a plurality of first fuel apertures 46 thatallows fuel to flow into the conduit element 38.

The conduit element 38 is of a length such that the second end 82 of theconduit element 38 abuts and sits within a cup 84 at the centre of thebase 78 of the filter bowl 8. The abutment of second end 82 in the cup84 has the advantage that when the filter bowl 8 is being screwed ontoconnection element 6 the cup 84 prevents any risk of the rotation of thefilter bowl 8 causing the second end 82 of the conduit element 38 tomove away from the centre of the filter bowl base 78 and potentially jamthe conduit element 38 in a skewed position in aperture 32.

The conduit element 38 is of such a length that when the second end 82of the conduit element 38 is in the cup 84 sufficient of the conduitelement 38 adjacent its first end 42 projects through the aperture 32toward the manifold 4 that the first fuel apertures 46 entirely mouthinto the second inlet chamber 20 as shown in FIGS. 4 and 5 and is theinlet shutoff valve in its open configuration. This allows fuel to flowfrom the second inlet chamber 20 through the first fuel apertures 46 andinto the conduit 86 of the conduit element 38.

The side wall 40 of the conduit element 38 further defines a number ofsecond fuel apertures 88 at a longitudinal position separated from thefirst fuel apertures 46 by a blank portion of the wall 90. Thelongitudinal dimension of the blank portion of the wall 90 is sufficientthat some or all of the second fuel apertures 88 mouth into the filterinlet chamber 92 irrespective of the position of the conduit element 38as it sits at the inlet shutoff valve open or closed configuration or atsome position between those two configurations.

The second outlet chamber 50 is in part defined by faces 52 and 54 ofthe manifold 4, in part by the radially outer face of chamber element 24and wall 56 of the connector element 6, and in part by the valve plug142. The face 52 of the manifold 4 defines a first outlet chamberaperture 60 and the wall 56 of the connector element 6 defines a numberof second outlet chamber apertures 58.

The first outlet chamber aperture 60 is the mouth of the outlet passage62 which extends to the fuel outlet port 12. The second outlet chamberapertures 58 are in communication with the outlet filter chamber 64.

In a loose sliding fit with and extending around the chamber element 24of the connector element 6 is a plate element 66. The plate element 66is dimensioned so as to overlie all of the second outlet chamberapertures 58 when the plate element 66 is in contact with the wall 56 ofthe connector element 6. The face of the plate element 66 which contactsthe wall 56 is proved with a flexible seal coating (not labelled) withthe result that when the plate element 66 is impelled into contact withthe wall 56 a fuel tight seal is created between the plate element 66and the wall 56 and fuel cannot then pass through the second outletchamber apertures 58. A biasing means 68 in the form of a compressionhelical spring is compressed between the face 54 of the manifold 4 andthe plate element 66 and impels the plate element 66 into contact withthe wall 56. When the plate element 66 is impelled into contact with thewall 56 and the second outlet chamber apertures 58 are sealed the plateelement 66 is the outlet shutoff valve and is in the outlet shutoffvalve closed configuration.

The filter element 110 has a second end 158 onto which is attached anoutlet shutoff valve engagement element 150. The outlet shutoff valveengagement element 150 is comprised of a plate 152 from which fourengagement pegs 154 are upstanding. The outlet shutoff valve engagementelement 150 is attached to the second end 158 of the fuel filter by anadhesive pad 156 with the upstanding pegs 154 extending away from thefilter element 110.

The wall 56 of the connector element 6 defines a number of apertures(not shown) which correspond in position to the positions of theengagement pegs 154 with the result that when the filter bowl 8 isattached to the connector element 6 while the filter element 110 ismounted on the spindle 114 the pegs 154 pass through the apertures (notshown), contact the plate element 66 and impel the plate element 66 awayfrom the wall 56 of the connector element 6 and into the outlet shutoffvalve open configuration (illustrated in FIG. 8a ).

When the filter bowl is detached from the connector element 6 the pegs154 stop impelling the plate element 66 into the outlet shutoff valveopen configuration and the biasing means 68 impels the plate element 66into the outlet shutoff valve closed configuration (illustrated in FIG.8b ).

The above description is meant to be exemplary only, and one skilled inthe art will recognize that changes may be made to the embodimentsdescribed without departing from the scope of the invention disclosed.Still other modifications which fall within the scope of the presentinvention will be apparent to those skilled in the art, in light of areview of this disclosure.

Various aspects of the fuel filters disclosed in the various embodimentsmay be used alone, in combination, or in a variety of arrangements notspecifically discussed in the embodiments described in the foregoing andthis disclosure is therefore not limited in its application to thedetails and arrangement of components set forth in the foregoingdescription or illustrated in the drawings. For example, aspectsdescribed in one embodiment may be combined in any manner with aspectsdescribed in other embodiments. Although particular embodiments havebeen shown and described, it will be obvious to those skilled in the artthat changes and modifications may be made without departing from thisinvention in its broader aspects. The scope of the following claimsshould not be limited by the embodiments set forth in the examples, butshould be given the broadest reasonable interpretation consistent withthe description as a whole.

1. A fuel filter comprising: a manifold, a connector element, a filterbowl, a filter element, an inlet shutoff valve, an outlet shutoff valve,an inlet port, an inlet passage, an outlet port, an outlet passage and arelief valve; wherein: the connector element is fixed to the manifold,and the filter bowl is reversibly fixed to the connector element, theconnector element and the manifold define a chamber and the chamber issplit into a second inlet chamber and a second outlet chamber by therelief valve, the filter bowl is adapted to reversibly receive thefilter element and is so configured that when the filter element islocated within the filter bowl and the filter bowl attached to theconnection element, the filter element divides the space defined by theconnector element and filter bowl into an inlet filter chamber and anoutlet filter chamber, the inlet port is incorporated in the manifold,and the inlet port and inlet filter chamber are in fluid communicationvia the inlet passage and the second inlet chamber, the outlet port isincorporated in the manifold and the outlet port and outlet filterchamber are in fluid communication via the outlet passage and the secondoutlet chamber, the inlet shutoff valve is biased by an inlet shutoffvalve biasing means into a closed configuration which prevents fuelflowing along the inlet passage when the filter bowl is not connected tothe connector element, connection of the filter bowl to the connectorelement causes the inlet shutoff valve to be impelled into an openconfiguration which allows fuel to flow along the inlet passage, theoutlet shutoff valve is biased by an outlet shutoff valve biasing meansinto a closed configuration which prevents fuel flowing along the outletpassage, the outlet shutoff valve is configured to move into a closedconfiguration which prevents fuel flowing along the outlet passage whenthe filter bowl with a filter element within it is not connected to theconnector element or there is no filter element within the filter bowl,and connection of the filter bowl with a filter element within it to theconnector element causes the outlet shutoff valve to be impelled into anopen configuration which allows fuel to flow along the outlet passage,the relief valve is biased by a relief valve biasing means into a closedconfiguration so that fuel flowing between the inlet passage and outletpassage has to pass through the filter element, and movement of therelief valve into an open configuration allows fuel to flow between theinlet passage and the outlet passage via the relief valve without thefuel passing through the filter element.
 2. The fuel filter according toclaim 1, wherein the impelling of the inlet shutoff valve and the outletshutoff valve into their open configuration commences after commencementof connection of the fuel filter bowl with the filter element within tothe connector element and before the fuel filter bowl is fully connectedto the connector element.
 3. The fuel filter according to claim 1,wherein: the second inlet chamber is defined by the manifold, theconnector element and a portion of the relief valve, and the portion ofthe second inlet chamber that is defined by the portion of the connectorelement has one or more side walls and a second end wall, the portion ofthe second inlet chamber that is defined by the portion of the connectorelement has a cross section in a plane parallel to the second end wallthat is the same at all positions in that portion, the manifold andconnector element defining the second inlet chamber also define a firstand second inlet chamber aperture respectively, the first inlet chamberaperture is a mouth of the portion of the inlet passage extending fromthe fuel inlet port, the second inlet chamber aperture passes throughthe second end wall and at least one sliding seal means extends aroundthe edge or inner face of the second inlet chamber aperture, the inletshutoff valve comprises a longitudinally extending conduit element, theconduit element is configured to extend through the second inlet chamberaperture in a fuel tight sliding engagement with the sliding seal means,the conduit element comprises a first flanged end, a second end, and oneor more side walls, the first end of the conduit element is closed, theflange of the first end of the conduit element comprises a flangeelement which extends laterally (relative to the longitudinal axis ofthe conduit element) from the first end of the conduit element and hasan outer edge spaced from the conduit element, the flange elementdefines at least one aperture passing through the flange, the flangeelement is dimensioned and configured so that its outer edge is insliding contact with the or each side wall of the second inlet chamber,the one or more side walls of the conduit element extend between thefirst and second ends and at least one side wall of the conduit elementdefines at least one first fuel aperture passing through the side wallat a position adjacent to or close to the first end, the conduit elementis biased by a first biasing means to move to a position where theflange element of the conduit element is impelled against the second endwall of the second inlet chamber, and a seal means adapted to seal eachof the flange apertures when the flange element of the conduit elementis impelled against the second end wall of the second inlet chamber isattached to one or both of the face of the flange plate facing thesecond end wall of the second inlet chamber and the face of the secondend wall of the second inlet chamber facing the flange plate.
 4. Thefuel filter according to claim 1, wherein: the second inlet chamber isdefined by the manifold, the connector element and a portion of therelief valve, and the portion of the second inlet chamber that isdefined by the portion of the connector element has one or more sidewalls and a second end wall, the portion of the second inlet chamberthat is defined by the portion of the connector element has a crosssection in a plane parallel to the second end wall that is the same atall positions in that portion, the manifold and connector elementdefining the second inlet chamber also define a first and a second inletchamber aperture respectively, the first inlet chamber aperture is amouth of the portion of the inlet passage extending from the fuel inletport, the second inlet chamber aperture passes through the second endwall and at least one sliding seal means extends around the edge orinner face of the second inlet chamber aperture, the inlet shutoff valvecomprises a longitudinally extending conduit element, the conduitelement is configured to extend through the second inlet chamberaperture in a fuel tight sliding engagement with the sliding seal means,the conduit element comprises a first end, a second end, and one or moreside walls, the first end of the conduit element is closed and providedwith a flange which extends laterally (relative to the longitudinal axisof the conduit element) from the first end of the conduit element, theone or more side walls of the conduit element extend between the firstand second ends, at least one side wall of the conduit element definesat least one first fuel aperture passing through the side wall at aposition adjacent to or close to the first end, the conduit element isbiased by a first biasing means to move to a position where the flangeof the conduit element is impelled against the second end wall of thesecond inlet chamber, and a seal means is provided which is adapted toseal the second inlet chamber aperture when the flange element of theconduit element is impelled against the second end wall of the secondinlet chamber.
 5. The fuel filter according to claim 4, wherein theconduit element further comprises: one or more second fuel apertureswhich are defined by one or more of the side walls of the conduitelement, and wherein: the one or more second fuel apertures are locatedlongitudinally between the one or more first fuel apertures and thesecond end of the conduit element, and the conduit element isdimensioned and configured so that when the filter bowl is fullyattached to the connector element the second end of the conduit elementabuts a part of the filter bowl, the apertures in the flange of theconduit element are not sealed, the first fuel apertures of the conduitelement open into the second inlet chamber, and the second fuelapertures of the conduit element open into the inlet filter chamber. 6.The fuel filter according to claim 3, further comprising: anintermediate structure, in which the second end of the conduit elementabuts a part of the filter bowl via the intermediate structure when thefilter bowl is fully attached to the connector element, and theintermediate structure is configured and dimensioned so that the biasingmeans may displace the intermediate structure and move the conduitelement into the closed configuration when the filter bowl is detachedfrom the connection element.
 7. The fuel filter according to claim 3,wherein: the portion of the manifold that partially defines the secondoutlet chamber defines a first outlet chamber aperture, the portion ofthe connector element partially defining the second outlet chamber alsodefines one or more second outlet chamber apertures, the first outletchamber aperture is a mouth of the portion of the outlet passageextending from the fuel outlet port, the or each second outlet chamberaperture is in fluid communication with the outlet filter chamber, andthe outlet shutoff valve comprises an aperture closure element, theaperture closure element is configured to overlie all of the secondoutlet chamber apertures and to be movable between a closedconfiguration in which the aperture closure element seals all of thesecond outlet chamber apertures and an open configuration spaced fromthe second outlet chamber apertures, and the aperture closure element isbiased into the closed configuration by the biasing means.
 8. The fuelfilter according to claim 7, wherein: the fuel filter comprises one ormore outlet intermediate structures, each outlet intermediate structureis dimensioned and configured to contact a portion of the filter elementat least when the filter bowl is fully attached to the connector elementand the filter element is within the filter bowl, each outletintermediate structure impels the aperture closure means into its openconfiguration when the filter bowl is fully attached to the connectorelement, and the filter element is correctly located within the filterbowl, and the one or more outlet intermediate structures allow thebiasing means to displace each of the outlet intermediate structures andmove the aperture closure means into the closed configuration when thefilter bowl and filter element are detached from the connection element.9. The fuel filter according to claim 1, wherein the relief valvecomprises a valve seat and a valve plug, the relief valve biasing meansbiases the valve plug against the valve seat, and the valve plug may beimpelled to move to a position spaced from the valve seat.
 10. The fuelfilter according to claim 1, wherein the valve plug has valve face witha frustoconical configuration and the valve seat is configuredaccordingly.
 11. The fuel filter according to claim 10, wherein: thevalve plug comprises a valve face, a pressure face, and one or morewalls that define a valve plug passage, the valve face is adapted toform a seal with the valve seat, the valve face extends around theoutside of the wall or walls that define the valve plug passage, theface of the wall or walls that face into the valve plug passagepartially define the second inlet chamber, the face of the wall or wallsthat face away from the valve plug passage partially define the secondoutlet chamber, and a first end of the wall or walls is connected to thevalve face by the pressure face.
 12. The fuel filter according to claim11 wherein the valve face has a frustoconical configuration and thepressure face joins to the smaller diameter edge of the frustoconicalvalve face.
 13. A fuel filter according to claim 1, in which at leastone of the inlet and outlet shutoff valve biasing means and the reliefvalve biasing means is a compression spring.
 14. A method of supplyingfuel to a combustor of a gas turbine engine comprising: passing the fuelthrough a fuel filter according to claim 1 prior to introduction of thefuel into the combustor.